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Klaviyo flow architecture: the data layer behind the triggers

A flow is only as good as the event that starts it and the properties that split it. Flow strategy - what a welcome series says, how many emails, when SMS joins in - is a marketing decision. Whether the trigger event fires reliably and carries the right data is an engineering one. This page covers the second half.

What actually triggers a flow

Every flow starts from a metric: a native event (Placed Order, Started Checkout, Viewed Product), a list/segment membership change, or a custom event sent through the Events API. The flow's filters and split conditions then read properties off that event or off the profile. If the event doesn't fire, or fires without the property a split depends on, the flow either never runs or runs down the wrong branch silently.

Where the standard flows break

FlowUnderlying eventCommon data failure
Welcome seriesSubscribed to List / Consented to receive SMSConsent recorded inconsistently across signup sources (popup, checkout, SMS keyword)
Abandoned cartStarted CheckoutCustom cart/subscription logic not wired into the e-commerce integration, so line items or totals are missing
Browse abandonViewed ProductClient-side tracking dropped by ad blockers or slow page loads, undercounting real browsing
Post-purchase / cross-sellPlaced Order (with line-item properties)Product category/collection properties missing, so the "customers who bought X" split can't evaluate
Win-back / churnPlaced Order recency, custom "Predicted next order" or subscription-status eventNo reliable recency or subscription-status event feeding the timing window

How we approach a flow data audit

  • Map every live flow to the event and properties it actually depends on.
  • Verify each event fires client-side and server-side where relevant, with the properties the flow's filters reference.
  • Check profile properties used in splits (customer tier, predicted CLV, subscription status) for staleness or missing values.
  • Flag flows silently running on incomplete data - the ones that never error, just underperform.

What we hand back is an event/property spec per flow, not a rewritten flow. Implementing the copy and structure changes stays with whoever owns your Klaviyo account day to day.

Common questions

Do you write the flow copy?

No. We build and verify the event and property layer a flow branches on - trigger events, timing, and split conditions. Copy, design, and send-timing strategy stay with your marketing team or creative agency.

Why would a flow trigger inconsistently?

Usually because the underlying event doesn't fire reliably (a JavaScript error, a missing server-side call, an integration gap) or because the flow's filter conditions reference a property that isn't always present on the profile at trigger time.

Can a flow trigger off a custom event?

Yes - any event sent to Klaviyo via the Events API, a native integration, or a tag can be used as a flow trigger, provided it carries the properties the flow's conditional splits need.

What's the most common flow data problem you see?

Abandoned cart and browse abandon flows built on the default e-commerce integration, which misses custom cart logic, multi-currency checkouts, or subscription products - so the flow either never fires or fires with the wrong item data.

Find out which flows are running on incomplete data.

An event/property audit across your live flows - documented findings, no rewritten copy.

Audit My Flow Triggers